European Patent Application EP 0489277 A1 discloses a gasket seal for a front portion of a housing (housing the gearbox) of a hammer drill. The housing is longitudinally divided into two parts, with the gasket seal located between the housing parts to seal the housing. An aperture is provided in the housing, a portion of which aperture is provided by each housing part. A rotary shaft extends through the aperture, supported by a bearing located in the aperture. The gasket seal includes an annular portion which extends around an external surface of the bearing to seal between the bearing and the housing.